function Martin(a,b,c,N)
f = @(x,y)(y-sign(x)*sqrt(abs(b*x-c)));
g = @(x)(a-x);
m = [0;0];
for n=1:N
    m(:,n+1)=[f(m(1,n),m(2,n)),g(m(1,n))];
end
plot(m(1,:),m(2,:),'kx','MarkerSize',1.5,'LineWidth',1.5);
axis equal